Need help w/ arranging resultant vector with 3 other vectors. D:

[Bensky]

Homework Statement

Find the vector combination R = A + 2B - C. Grid lines are separated by 1 cm. When you submit your answer the third vector that you drew may disappear, but if you are correct you will have a green check mark near the grid. (Mac OS X use Netscape, Windows use IE.) A scratch vector is provided for your use if needed.

http://xs220.xs.to/xs220/07430/vectorhelp2.PNG

Homework Equations

none

The Attempt at a Solution

A x=-3 y=2
B x=-1 y=-1
C x=-2 y=1
R x=-3 y=-1

I tried using the tip to tail method for joining the vectors, but it didn't work since the vectors don't fit. Maybe I have to use the parallelogram method here? I really have no idea. :( Any help is appriciated.

 

[hotcommodity]

You already know the equation for the resultant, and the components of each vector. If I have an equation for the resultant, say R = 2A - B, where A and B are vectors, and I know that A = < 1, 2 >, and B = < 3, 4 >, I can find the resultant by plugging the vector components into the resultant equation:

R = 2< 1, 2 > - < 3, 4 > = < 2, 4 > - <3, 4 >

Add the components:

< 2, 4 > - <3, 4 > = < -1, 0 >

Now we know that the resultant should be the vector < -1, 0 >, where -1 is the x component, and 0 is the y component.

 

[Bensky]

You already know the equation for the resultant, and the components of each vector. If I have an equation for the resultant, say R = 2A - B, where A and B are vectors, and I know that A = < 1, 2 >, and B = < 3, 4 >, I can find the resultant by plugging the vector components into the resultant equation:

R = 2< 1, 2 > - < 3, 4 > = < 2, 4 > - <3, 4 >

Add the components:

< 2, 4 > - <3, 4 > = < -1, 0 >

Now we know that the resultant should be the vector < -1, 0 >, where -1 is the x component, and 0 is the y component.

Thanks, but I already have found the components of the vectors. I was asking how to do the graphical part, like where you arrange the vectors and the resultant. >_>

 

[Siracuse]

Look at your equation, there's a minus signal in front of vector C. That equals to the sum of vector C, just in a opposite direction.